Apparatus, system, and method for a firearm conversion kit

ABSTRACT

An apparatus is disclosed for a firearm conversion kit. The apparatus includes left and right hand portions configured to form furniture of a firearm having a trigger, a remote trigger coupled with a platform, the platform extending into a slot in at least one of the left and right hand portions, and a single linkage rod coupling the remote trigger to a trigger engagement device configured to actuate the trigger when the remote trigger is actuated.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Patent Application No. 61/510,881 entitled “Firearm Conversion Kit” and filed on Jul. 22, 2011 for Bjorn Muller, which is incorporated herein by reference.

FIELD

This invention relates to firearms and more particularly relates to bullpup-style firearm conversion kits.

BACKGROUND

Conventional firearms are configured such that the firing trigger is situated below and/or behind the action of a firearm. In a bullpup-style configuration, on the other hand, the action is located behind the firing trigger. By moving the firing trigger in front of the action, no space is wasted for the rear stock of the firearm, as in conventional firearm configurations. The bullpup-style design permits a shorter firearm length, while maintaining the same barrel length, thus reducing the overall weight of the firearm and allowing for improved maneuverability.

Many conventional firearms may be converted to a bullpup-style configuration with a conversion kit. In some bullpup-style conversion kits, however, the remote trigger linkage assembly does not provide a realistic feeling trigger squeeze similar to the trigger squeeze of the original firing trigger. Moreover, other bullpup-style conversion kits can be tedious to assemble, requiring many parts or modifications to the original firearm action and/or trigger.

SUMMARY

From the foregoing discussion, it should be apparent that a need exists for an apparatus, system, and method that converts a conventional firearm to a bullpup-style configuration. Beneficially, such an apparatus, system, and method would provide a more reliable trigger linkage system and easier conversion assembly.

The present invention has been developed in response to the present state of the art, and in particular, in response to the problems and needs in the art that have not yet been fully solved by currently available bullpup-style firearm conversion kits. Accordingly, the present invention has been developed to provide an apparatus, system, and method for converting a conventional firearm to a bullpup-style configuration that overcomes many or all of the above-discussed shortcomings in the art.

The apparatus, in one embodiment, includes left and right hand portions configured to form the furniture of a firearm with a firing trigger. A remote trigger, in some embodiments, is coupled with a movable platform which extends into a slot in at least one of the left and right hand portions of the firearm furniture. In one embodiment, a single linking rod couples the movable platform to a trigger engagement device. The trigger engagement device, in another embodiment, is configured to actuate the firing trigger when the remote trigger is actuated.

A system of the present invention is also presented to convert a conventional firearm to a bullpup-style configuration. In particular, the system, in one embodiment, includes a bolt assembly, a trigger assembly, a barrel, and a magazine. In one embodiment, the trigger assembly, including a firing trigger, and the barrel are coupled to the bolt assembly. The magazine is also connected to the bolt assembly, but may be removed in some embodiments.

The system may further include, in one embodiment, left and right hand portions configured to form the furniture of a firearm with a firing trigger. In some embodiments, a trigger is coupled to a movable platform which extends into a slot in at least one of the left and right hand portions. Also included in other embodiments is a single linkage rod which couples the movable platform to a trigger engagement device. The trigger engagement device, in one embodiment, is configured to actuate the firing trigger when the remote trigger is actuated.

A method of the present invention is also presented for converting a conventional firearm to a bullpup-style configuration. The method in the disclosed embodiments substantially includes the steps necessary to carry out the functions presented above with respect to the operation of the described apparatus and system. In one embodiment, the method includes removing the original furniture of the firearm and placing the firearm between the left and right hand portions of the conversion kit, which are configured to form the furniture of a firearm having a firing trigger. The method, in some embodiments, may include connecting a remote trigger to the firing trigger using a linkage assembly and fastening the firearm between the left and right hand furniture portions by attachment means using attachment points located on the firearm furniture.

Reference throughout this specification to features, advantages, or similar language does not imply that all of the features and advantages that may be realized with the present invention should be or are in any single embodiment of the invention. Rather, language referring to the features and advantages is understood to mean that a specific feature, advantage, or characteristic described in connection with an embodiment is included in at least one embodiment of the present invention. Thus, discussion of the features and advantages, and similar language, throughout this specification may, but do not necessarily, refer to the same embodiment.

Furthermore, the described features, advantages, and characteristics of the invention may be combined in any suitable manner in one or more embodiments. One skilled in the relevant art will recognize that the invention may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments of the invention.

These features and advantages of the present invention will become more fully apparent from the following description and appended claims, or may be learned by the practice of the invention as set forth hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the advantages of the invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:

FIG. 1 is an exploded side view diagram illustrating one embodiment of a firearm conversion kit relative to a firearm in accordance with the present subject matter;

FIG. 2 is a side view diagram illustrating another embodiment of the firearm conversion kit coupled to a firearm in accordance with the present subject matter;

FIG. 3 is a side view diagram illustrating one embodiment of a left hand portion of a firearm conversion kit with a remote trigger assembly in accordance with the present subject matter; and

FIG. 4 is a perspective view diagram illustrating one embodiment of a remote trigger linkage assembly of a firearm conversion kit in accordance with the present subject matter.

DETAILED DESCRIPTION

Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment.

Furthermore, the described features, structures, or characteristics of the invention may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

As shown in FIG. 1, and according to one embodiment, a firearm conversion kit (hereinafter “kit”) 100 converts a firearm 101 to a configuration in which the action or bolt assembly 102 is located closer to a shooter than the trigger (e.g., remote trigger 104). Such a configuration is referred to as a “bullpup” configuration, and is achieved by connecting an actual or original trigger 106 of the firearm 101 to the remote trigger 104 via a linkage 105 as will be discussed in more detail below.

The kit 100 includes left and right hand portions 108, 110, that, when joined together, form the so-called “furniture” of the firearm. Generally, the firearm 101 includes an ammunition magazine 112, a barrel 114, the trigger assembly 106, and a bolt assembly 102. The remaining parts of the firearm 101, such as the stock, are often referred to as the furniture of the firearm and may be removed without affecting the functionality of the firearm. The depicted embodiment illustrates a firearm 101 with the furniture removed so that the kit 100 may be attached to the firearm 101. The firearm 101 may be a shotgun or a rifle. Depicted here is a Kalashnikov-style shotgun for illustrative purposes only, as the kit 100 may be adapted to many different styles of rifles, pistols, and shotguns.

The kit 100 is configured with attachment points 118 for coupling the left and right hand portions 108, 110 together around the firearm 101. The left hand portion 108 has attachment points 118 that correspond with the attachment points 118 of the right hand portion 110. In a further embodiment, the left and right hand portions 108, 110 may include attachment points 118 that correspond with attachment points 120 of the firearm 101. Stated differently, the left and right hand portions 108, 110 may include attachment points 118 that align with openings in the firearm 101 for receiving screws, for example.

In one embodiment, the left or right hand portions 108, 110 may be separated into distinct pieces. For example, as shown in FIG. 1, the right hand portion 110 includes separate forward and rear sections 110 a, 110 b. With the right hand portion 110 including multiple separate sections, the kit 100 is capable of accommodating the bolt assembly 102 of the firearm 101. In other words, the right hand portion 110 is formed according to the specific configuration of the firearm 101, and may be separated into forward and rear sections. In an alternative embodiment, the left hand portion 108 may be separated in a similar manner to accommodate firearms 101 that eject cartridges to the left, instead of to the right as depicted in FIG. 1.

In a further embodiment, the kit 100 may include cutouts to accommodate moving parts of the firearm 101. For example, the right hand portion 110 includes cutouts 122 to allow a sliding bolt action to move freely. The left and right hand portions 108, 110 may also include ventilation ports 123 for cooling the barrel 114 of the firearm 101.

In yet another embodiment, the kit 100 may include a gas adjustment lever 124 for modifying firearms 101 that utilize gas-operated reloading. Gas-operated reloading systems use a portion of high pressure gas from a cartridge being fired to power a mechanism that extracts the spent cartridge case and inserts a new cartridge. This mechanism, as in the depicted embodiment, may include a gas cylinder 126 positioned adjacent the barrel 114. As gas operated reloading systems are known to those of skill in the art, further explanation is not warranted. The gas adjustment lever 124 is positioned in either the left or right hand portion 108, 110 according to the position of a gas cylinder adjustment device of the firearm, which will vary depending upon the particular firearm 101 for which the kit 100 is designed to fit. In the depicted embodiment, using a Kalashnikov style firearm, the gas adjustment lever 124 is positioned in the right hand portion 124 in a forward location near the forward end of the gas cylinder 126. As used herein, the term “forward” refers to an end of the firearm 101 opposite a shooter. In other words, the “forward” end of the barrel 114 is the end through which a projectile exits the barrel 114.

Referring to FIG. 2, the kit 100 converts the firearm 101 into a bullpup-style firearm having a trigger 104 in front of both the bolt assembly 102 and magazine 112 as discussed above. The firearm 101 is disposed between the left and right hand portions (the right hand portion 110 being visible in FIG. 2), with the kit 100 forming the furniture or stock of the firearm, which includes a shoulder stock 202 and a fore end 204. The shoulder stock 202 covers the original trigger 106 shown in FIG. 1 and also provides support for the linkage 105 that mechanically connects the remote trigger 104 to the original trigger 106.

FIG. 3 is a side view diagram illustrating one embodiment of the interior of the left hand portion 108. The kit of FIG. 1, in one embodiment, is formed of a rigid and resilient plastic, for example, high-impact and heat-stabilized glass-filled nylon. Alternatively, the kit 100 may be formed of any suitable light weight material, including but not limited to, ABS, fiberglass, carbon fiber, and other composite, polymer, or natural materials.

The depicted left hand portion 108 is formed with reinforcing ridges or webbing 302 positioned throughout the interior of the left hand portion 108. Similarly, although not depicted here, the right hand portion 110 is formed with corresponding reinforcing ridges. The ridges 302, in one embodiment, are shaped to matingly engage and support a firearm (e.g., firearm 101). Different firearms will have different surface profiles and therefore require a different profile of the reinforcing ridges 302.

The left hand portion 108 is formed having a slot 304 for receiving a sliding remote trigger 306 of a linkage assembly 301. The sliding remote trigger 306 is coupled with a platform 308 that extends outward from the trigger 306 and engages the slot 304. Although the platform 308 is shown extending outward into the slot 304 of the left hand portion 108, in certain embodiments, the platform 308 can also extend into a corresponding slot formed in a right hand portion. A riser 310 couples the platform 308 with a linkage 312. The riser 310 may be laterally and vertically offset from the remote trigger 306 and platform 308. The linkage 312, in one embodiment, is a solid, rigid rod that mechanically connects the trigger 306 with the trigger 106 of a firearm as depicted in FIG. 1. The solid nature of the linkage rod 312 results in a stiff trigger squeeze that feels substantially similar to the trigger squeeze of the original trigger. Stated differently, because the linkage rod 312 is a single piece, pulling the remote trigger does not result in a compressible-feeling linkage like other firearm conversion kits. Preferably, the linkage 312 is made from a metal, such as steel or aluminum. However, in some embodiments, the linkage is made from a plastic.

The ridges 302 of the left hand portion 108, or right hand portion 110, may be configured with openings for receiving the linkage 312 to maintain and guide the sliding movement of the linkage 312. In a further embodiment, one end of the linkage 312 may extend through the stock end 313 of the left hand portion 110. Additionally, the ridges 302 may collectively define a slot within which the linkage is positioned to maintain the linkage in alignment with the riser 310 and the stock end 313. The left hand portion 108 is depicted here because firearms typically discharge shells to the right side of the firearm, and therefore, the left hand portion 108 does not require an opening for the bolt assembly. As such, the linkage 312 may be embedded in the left hand portion 108 and therefore, not visible when the left hand portion 108 is mated to the right hand portion 110. However, in certain embodiments, as one skilled in the art will recognize, the linkage 312 may be adapted to kits 100 that are designed for firearms that discharge shells to the left, top, bottom, or front of the firearm.

FIG. 4 is a perspective view diagram illustrating one embodiment of a linkage assembly 400 similar to linkage assemblies 105, 301 discussed above. The linkage assembly 400 mechanically couples a remote trigger 306 with an original trigger of a firearm. The linkage assembly 400 includes the linkage rod 312, which couples the remote trigger 306 to the original trigger. When a shooter pulls the remote trigger 306, the trigger movement is translated through the linkage rod 312 to a trigger engagement device 314. The trigger engagement device 314 is formed, in one embodiment, of a lightweight rigid material having a low coefficient of friction. For example, the trigger engagement device 314 may be formed of PTFE, or other lightweight rigid polymers having low coefficients of friction. The trigger engagement device 314 may be formed as a cylinder of the lightweight rigid polymer, and secured to the linkage rod via a fastening device 315, for example, a nut secured to a threaded rod.

The trigger engagement device 314 is coupled to the linkage rod 312 by a carrier 320 that includes a rod engagement element 322 and a spacer element 324 extending downwardly from the rod engagement element. The rod engagement element 322 includes an interior channel (not shown) through which the linkage rod extends. The spacer element 324 couples the trigger engagement device 314 and the rod engagement element 322. In one implementation, the length of the spacer element 324 positions the trigger engagement device 314 in vertical alignment with the original trigger of the firearm and the remote trigger 306. Accordingly, the linkage assembly 400 includes a linkage rod 312 that is offset from the actual trigger of the firearm and the remote trigger 306, but includes a carrier 320 that positions the actual trigger engagement device 314 in alignment with both the remote and actual triggers. In this manner, the linkage rod 312 need not be in direct alignment between the remote and actual triggers in order to facilitate a responsive and natural feel when engaging the remote trigger to actuate the actual trigger. The carrier 320 is preferably made from a metal, but in certain implementations, can be made from a plastic material.

As described above in FIG. 3, the remote trigger 306 is formed having a platform 308 that extends outward from the remote trigger 306 into at least one of the left or right hand portions 108, 110. In the depicted embodiment, the platform 308 extends into both the left and right hand portions 108, 100, and inserts into corresponding slots formed in the left and right hand portions 108, 110. The platform 308 serves to guide the remote trigger 306. Extending from the platform 308 is the riser 310 which couples with the linkage rod 310 to place the rod vertically and laterally offset from the remote trigger. These above described elements may be formed as a single, unitary linkage assembly 400, or alternatively, as individual elements assembled to form the linkage assembly 400.

The linkage assembly 400, in one embodiment, includes a helper spring 316 that compresses as the remote trigger 306 is pulled, and therefore, helps return the remote trigger 306 to a default or resting position. One end of the helper spring 316 engages the riser 310 of the linkage assembly 400, and the opposite end may engage a reinforcing ridge of either the left or right hand portion 108, 110. Certain firearms do not require the use of a helper spring 316 as the original trigger will provide enough force to return the remote trigger 306 to the default position.

In a further embodiment, the linkage assembly 400 includes adjustment devices 318 for adjusting the fore and aft positioning of the trigger engagement device 314. The adjustment devices 318 may comprise nuts threadably engaged with a threaded area of the linkage rod 312. In other words, the adjustment devices 318 may be rotated on a threaded area of the linkage rod 312 to adjust the fore and aft position of the carrier 320, which is slidable along the threaded area, and thus the trigger engagement device 314.

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. 

What is claimed is:
 1. An apparatus comprising: left and right hand portions configured to form furniture of a firearm having a firing trigger; a remote trigger coupled with a movable platform, the platform extending into a slot in at least one of the left and right hand portions; and a single linkage rod coupling the movable platform to a trigger engagement device configured to actuate the firing trigger when the remote trigger is actuated.
 2. The apparatus of claim 1, wherein the furniture comprises a fore end and a stock end of the firearm.
 3. The apparatus of claim 1, further comprising a helper spring configured to return the remote trigger to a default position.
 4. The apparatus of claim 1, further comprising adjustment devices coupled with the trigger engagement device and configured to adjust the position of the trigger engagement device relative to the linkage rod and the firing trigger.
 5. The apparatus of claim 1, further comprising a riser coupled to the single linkage rod, the riser placing the single linkage rod vertically and laterally offset from the remote trigger.
 6. The apparatus of claim 1, wherein the left and right hand portions include corresponding attachment points for securely fastening the firearm between the left and right hand portions.
 7. The apparatus of claim 1, wherein the left and right hand portions are formed of a rigid plastic that includes reinforcing ridges.
 8. The apparatus of claim 1, wherein the left and right hand portions include separate forward and rear sections.
 9. A firearm comprising: a bolt assembly; a trigger assembly, including a firing trigger, coupled to the bolt assembly; a barrel coupled to the bolt assembly; a magazine removably connected to the bolt assembly; left and right hand portions configured to form furniture of the firearm having a firing trigger; a remote trigger coupled with a movable platform, the platform extending into a slot in at least one of the left and right hand portions; and a single linkage rod coupling the movable platform to a trigger engagement device configured to actuate the firing trigger when the remote trigger is actuated.
 10. The firearm of claim 9, wherein the furniture comprises a fore end and a stock end of the firearm.
 11. The firearm of claim 9, further comprising a helper spring configured to return the remote trigger to a default position.
 12. The firearm of claim 9, further comprising adjustment devices coupled with the trigger engagement device and configured to adjust the position of the trigger engagement device relative to the linkage rod and the firing trigger.
 13. The firearm of claim 9, further comprising a riser coupled to the single linkage rod, the riser placing the single linkage rod vertically and laterally offset from the remote trigger.
 14. The firearm of claim 9, wherein the left and right hand portions include corresponding attachment points for securely fastening the firearm between the left and right hand portions.
 15. The firearm of claim 9, wherein the left and right hand portions are formed of a rigid plastic that includes reinforcing ridges.
 16. The firearm of claim 9, wherein the left and right hand portions include separate forward and rear sections.
 17. A method for converting a firearm, the method comprising: removing the original furniture of the firearm; disposing the firearm between left and right hand portions configured to form furniture of a firearm having a firing trigger; connecting a remote trigger to the firing trigger by means of a linkage assembly; and fastening the firearm between the left and right hand portions by attachment means using attachment points disposed on the firearm furniture.
 18. The method of claim 17, wherein the linkage assembly includes a helper spring configured to return the remote trigger to a resting position and adjustment devices for adjusting the fore and aft position of the remote trigger.
 19. The method of claim 17, wherein the linkage assembly includes adjustment devices coupled with the trigger engagement and configured to adjust the position of the trigger engagement device relative to the linkage rod and the firing trigger.
 20. The method of claim 17, wherein the linkage assembly comprises one or more of a single component and individual elements that form the linkage assembly when assembled. 